It is an effective way to achieve green energy and the sustainable development of energy by collecting energy from the living environment, which has been paid attention to by the whole world. The piezoelectric technology, as a new energy development technology, is widely used in various industrial fields and expected to play important roles in environmental monitoring, energy-saving systems, implantable medical means, and even consumer electronics.
The piezoelectric technology is the technology based on a piezoelectric effect. When the dielectric is deformed due to an external force in a certain direction, its interior will generate polarization phenomenon, and positive and negative charges will appear on its two opposite surfaces. When the external force is removed, it will return to a non-charged state, and this phenomenon is called a positive piezoelectric effect. When the direction of the acting force changes, the polarity of the charge also changes.
It can be understood that the essence of the piezoelectric effect is that the mechanical action causes dielectric polarization. As for the displacement of the ionic charge in the crystal, when no strain exists, the distribution of charges on lattice positions is symmetrical, its internal electric field is zero. When a stress is applied to the crystal, the charge is displaced. If the charge distribution is no longer symmetrical, the net polarization occurs and produces an electric field accordingly. The electric field will appear as the piezoelectric effect. A type of sensor developed based on the piezoelectric effect of the dielectric is called a piezoelectric sensor.
When a conventional piezoelectric element is in use, wires are usually connected to upper and lower surfaces of a piezoelectric part of the piezoelectric element to form a loop, and the charge generated by the piezoelectric effect is derived through the wires, to supply to loads for use. The existing piezoelectric element has low sensitivity.
It should be noted that, information disclosed in the above background portion is provided only for better understanding of the background of the present disclosure, and thus it may contain information that does not form the prior art known by those ordinary skilled in the art.